Journal article
Hot branching dynamics in a light-harvesting iron carbene complex revealed by ultrafast x-ray emission spectroscopy
Lund University1
Stanford University2
Department of Physics, Technical University of Denmark3
Neutrons and X-rays for Materials Physics, Department of Physics, Technical University of Denmark4
Hungarian Academy of Sciences5
SLAC National Accelerator Laboratory6
German Electron Synchrotron7
Department of Chemistry, Technical University of Denmark8
Iron nitrogen heterocyclic carbenes (NHC) have received a great deal of attention recently, due to their growing potential as e.g light sensitizers and photocatalysts. We present a sub-ps x-ray spectroscopy study of a FeIINHC complex allowing us to identify and quantify the states involved in the deactivation cascade after light absorption.
We find that excited molecules relax back to the ground state populating first the 3MLCT and then along two pathways the 3MC state. One of these pathways is ultrafast (~150 fs) for ~30% of the excited molecules, in competition with vibrational relaxation and cooling, followed by a much slower (7.6 ps) decay of the relaxed 3MLCT state.
The 3MC state then rapidly (2.2 ps) decays to the ground state. The ultrafast deactivation of the 3MLCT state constitutes a loss channel from the point of view of photochemical efficiency and highlights the necessity to screen other FeNHC complexes (and perhaps other transition metal complexes) for this ultrafast decay of 3MLCT population, in order to optimize photochemical performance.
Language: | English |
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Year: | 2020 |
Pages: | 364-372 |
ISSN: | 15213773 and 14337851 |
Types: | Journal article |
DOI: | 10.1002/anie.201908065 |
ORCIDs: | 0000-0002-9777-2685 , 0000-0002-2056-6883 , 0000-0003-2474-6264 , 0000-0002-0531-5138 , 0000-0002-4091-0899 , 0000-0001-7155-2011 , 0000-0003-4823-2188 , 0000-0001-9897-5380 , 0000-0003-0271-4173 , 0000-0002-2322-6403 , 0000-0003-2669-9473 , 0000-0001-5314-4612 , Biasin, Elisa , Vester, Peter , 0000-0002-6626-7301 , Haldrup, Kristoffer , 0000-0002-4399-1890 , 0000-0003-2084-078X , 0000-0002-8469-5887 , 0000-0002-3095-6551 , 0000-0003-4070-3168 , 0000-0002-6172-7946 , 0000-0002-2937-6074 , 0000-0003-1577-8643 , 0000-0003-4337-8129 , Dohn, Asmus O. , Møller, Klaus B. , Nielsen, Martin M. , 0000-0002-9022-3165 , 0000-0001-7049-6396 , 0000-0001-7600-3230 and 0000-0002-0528-0422 |
femtochemistry molecular dynamics photochemistry photophysics